In the present proposal we plan to investigate, indepth, the precise role of carbohydrates in the intracellular processing, segregation, stabilization and export of glycoproteins. We plan to investigate the following: 1. The role of carbohydrates in the stabilization of glycoproteins will be examined in vitro by using polyasparagine model peptides and fibronectin (FN). 2. The role of carbohydrates and/or carbohydrate-binding proteins in the intracellular segregation of glycoproteins will be examined by studying FN in chick embryo fibroblasts (CEF), acetylcholine receptor (AChR) and acetylcholine esterase (AChE) in muscle cells, and glycoprotein (G) of vesicular stomatitis virus (VSV) in mouse L cells. For these studies we initially plan to use inhibitors of glycosylation (tunicamycin and/or interferon), and lectin-specific sugar analogs to disrupt any possible signal between the carbohydrate side chains and intracellular carbohydrate binding proteins. Finally, we will attempt to isolate mutants of muscle cells (L6) deficient in the major, Beta-galactoside binding lectin. 3. We plan to determine the role of carbohydrate in the expression of the biological and pharmacological properties of the AChR. We are interested in determining if the carbohydrate groups play any role in the function of the receptor as a transducer, in the clustering of receptors at synapses, or in neuronal recognition.